Bacteria Species and Mechanisms (Pathophys) - Block 1 Flashcards
1
Q
List G+ cocci
A
- Staphylococcus (aureus, epidermidis, saprophyticus)
- Streptococcus pyogenes (Group A)
- Streptococcus pneumoniae
- Strep agalactiae (Group B)
- Viridans strep
- Enterococcus (faecalis, faecium)
2
Q
What makes are Staph similar?
A
Catalase + -> aerobic
3
Q
What is the most pathogenic staph?
A
Aureus
4
Q
Staphylococcus aureus
Differentiation, Location, Transmission, Disease
A
Differentiation:
* Catalase +
* Coagulase +
* G+
Location: skin, GI, GU
Transmission: person-person, direct, fomite
Dx: Toxin mediated, pyogenic
5
Q
What are examples of toxin mediated dx?
A
Food poisoning, TSS, Scalded skin syndrome
6
Q
What are examples of pyogenic dx?
A
Impetigo, folliculits, wound infection
7
Q
What are the virulence factors of S. aureus?
A
- Encapsulated
- Teichoic acid (adhesion)
- MSCRAMMS -> biofilm
- Protein A that binds to IgG blocking complement binding
- Coagulase
- Lipases, hyaluronidase, fibrinolysin
- CYtotoxins (a, b, d, g)
- Exofoliative toxins (ETA, ETB)
- Enterotoxins (A to R)
- TSS toxin 1 (TSST-1)
8
Q
What is the function of exofoliative toxins?
A
Serine proteases that breakdown the connections between stratum granulosum epidermis
9
Q
What is enterotoxins?
A
Superantigens that stmulates T cell proliferation and release of cytkines and stimulates mediator release from mast cells -> nausea and vomiting
10
Q
What is TSST-1?
A
Superantigen that stmulates T cell proliferation and release of cytokines and can cause endothelial leakage as well as cellular damage of endothelial cells
11
Q
What is the difference between food-poisoning and foodbourne illness?
A
Food poisoning: preformed toxins that doesn’t require bacterial growth
Foodbourne illness: Requirs microbial growth within the host
12
Q
How does the composition of MRSA diffferent from VRSA?
A
Meethicillin RSA: contains mecA gene that codes for PBP2a (lower affintiy for beta-lactams and methicillin)
Vancomycin RSA: contains van genes that change peptidoglycan precursors reducing vancomycin binding affinity
13
Q
Staphylococcus epidermis
Differentiation, Location, Transmission, Diseases
A
Differentiation:
* Catalase +
* Coagulase -
* Urese -
* G+
Location: skin, conjunctiva, nose, GU
Transmission: person-person, direct, fomites
Dx: bacteremia, opportunistic
14
Q
VF of S. epidermidis
A
- Encapsulated
- Slime layer
- Cytotoxin (delta)
15
Q
Staphylococcus saprophyticus
Differentiation, Location, Transmission, Diseases
A
Diff:
* Catalase +
* Coagulase -
* Urease +
* G+
Location: perineum, rectum, urethra, cervix, GIT
Trasmission: sexually active females and catheters
Dx: Dysuria, pyuria
16
Q
VF of S. saprophyticus
A
- Urease
- Non-hemolytic
17
Q
Staph that has B-hemolysis?
A
Aureus
18
Q
Staph’s response to mannitol salt agar?
A
Aureus: yellow colonies
Epidermis: pink/white
19
Q
What staph presents with a + urease?
A
Saprophyticus
20
Q
What Staph is coagulase +? -?
A
+: aureus
-: epidermis, saprophyticus
21
Q
What are the common characteristcs of Streptococcus?
A
SOD+, catalase +
22
Q
What is Strep calassified
A
- Lancefield groupings
- Hemolytic patterns
23
Q
Streptococcal pyogenes
Classifications, Location
A
Classification:
* Group A
* b-hemolytic
Location: Upper respiatory, GUT
24
Q
VF of Streptococcal pyogenes?
A
- Hyaluronic acid capsule
- M protein
- Adhesions
- C5a peptidase
- Hyaluronidase and streptokinase
- Cytotoxins (Steptolysin S and Streptolysin O)
- Streptococcal pyrogenic exotoxin
25
Streptococcus pneumoniae
| Classifications, Location, Transmisson, Diseases
**Classifications:**
* No cell wall
* a-hemolytic
* Facultative anarobe
* diplococci
**Location:** upper resp
**Transmission:** respiratory droplets
**Dx:** otits media, CAB pneumonia
26
VF of S. pneumoniae
1. Capsule
2. IgA protease
3. H2O2
4. Pneumolysin
27
Streptococcus agalactiae
| Classifications, Locaton, Diseases
**Classification:**
* Group B
* Capsule
* B-hemolytic
**Location:** UT, GIT
**Dx:** Neonatal sepsis, pneumonia, meningitis, and bacteremi
28
Viridans streptococci
| Classifications, Location, Disease
**Classification:**
* Green pigment colonies
* Non-capsulated
* Catalase -
* a-hemolytic/nonhemolytic
**Location:** oropharynx, GI, GU
**Dx:** dental infection, endocarditits
29
Enterococcus
| Classification, Location, Transmission, Disease
**Classification:**
* Group D
* Facultative anaerobes (catalase -)
* Oxidase -
* E. faecalis: gamma non-hemolyic
* E. faecium: a-hemolyic (MDR)
**Location:** GI
**Transmission:** nosocomial, patient-patient
**Dx:** UTI
30
VF of enterococcus?
Biofilms
31
G+ bacilli that form spores?
Bacillus and clostridium
32
G+ bacilli that don't form spores
Corynebacterium, Listeria
33
Bacillus cereus
| Classification, Location, Disease
**Classification:**
* Spore forming
* Opportunisitc
* B-hemolytic
* Facultative anaerobe
* Catalase +
* Oxidase -
**Location:** from contaminated soil
**Disease:** Gastroenteritis, ocular infection
34
What are the types of enterotoxins produced by Bacillus cereus?
**Heat stable:** , proteolysis-resistant toxin causes emetic form of disease -> food poisoning
**Heat labile:** enterotoxin causes the diarrheal form -> foobourne
35
Costridium perfrigens
| Classification, Location, Disease
**Classification:**
* Capsulated
* Non-motile
* SPore forming
* B-hemolytic inner zone, a-hemolytic outer
* Obligate anaerobe (catalase -)
**Location:** GI
**Dx:** soft tissue infections
36
VF of costridium perfringens?
1. Enzymes: collagenase, proteases, and hyaluronidase
2. Cytotoxin: phospholipase C lyses host cells
3. Enterotoxin and can cause food poisoning
4. Fermentation -> gas gangrene
37
Clostridioides (Costridium) difficile
| Classification, Location, Disease
**Classification:**
* Anaerobic
* Spor forming
* Dysbiosis
**Location:** GIT
**Disease:** CDAD, PMC
38
How does C. diff become infectious?
1. Produces toxin A (excessive fluid secretion) and B (cytotoxin)
2. Occurs in stationary phase
3. ID'd by ELISA in fecal sample
39
What are the large G+ bacilli?
1. Bacillus cereus
2. Costridium perfrigens
3. C. diff
40
Listeria monocytogenes
| Classification, Location, Disease
**Classification:**
* Catalase +
* weakly b hemolytic
* Facultatitve intracellular anaerobe
**Location:** Laboratory testing: gram stain of sterile samples (blood/CSF) and culture on blood agar
**Dx:** listerosis, menigitis, pregnant femal, neonates, elders, ICU
41
Describe how listeria is incorporated into the body?
1. Adheres to enterocytes by listeria adhesion protein and internalin A
2. Produces cytolysisns that allows it to escape phagolysosome to cytosol
3. Multiples move to cell membrane to go to another cell (infected cell dies)
4. Listeria is taken up by phagocytosis and distributed in the body
5. Penetrates microglia and neurons in CNS
42
Corynebacterium diphtheriae
| Classification, Disease
1. Facultative anaeobes
2. COntagious through resp drops, direct contact, fomites
3. Releases diptheria toxin
**Dx:** diptheria, pharyngitis, endocarditis
42
What is the mechanism of diphtheria toxin?
1. Exopoxin is produced when lysogenized by bacteriophage carrying the toxin gene
2. Creation of pseudomembran in throat -> respiratory obstruction -> toxemia
43
How can you prevent Corynebacterium diphtheriae infection?
DTaP toxoid vaccine
44
Nocardia
| Classification, Location, Transmission, Disease
**Classification:**
* partially acid fast
* Mycolic acid
* Strict aerobe
* Catalase +
* SOD +
* Blocks acidification of lysosome in order to replicate and survive
**Location:** lungs, skin, brain
**Transmission:** Inhalation, trauma
**Dx:** pulmonary, cutaneus, CNS infections
45
What are the small G+ bacilli?
1. Listeria
2. Corynebacterium diphtheriae
46
Examples of branching G+ bacilli?
Nocardia
47
VF of Neisseria
1. Lipooligosaccharide (LOS, endotoxin) lack the repeating O antigen
2. Encampsulated
3. IgA protease
4. Pili
48
What are the common characteristics of Neisseria?
1. Obligate aerobe
2. Fastidious
3. Oxidase +
4. Catalase +
49
Neisseria menigtides
| Location, Transmission, Disease
**Location:** nasopharynx
**Transmission:** respiratory droplets
**Disease:** CAB meningitis
* Conjugate meningococcal vaccine is available
50
What is the 2nd most common STI?
N. gonorrheae
51
Neisseria gonorrhoeae
| Location, Transmission, Disease
**Location:** vagina, urethral, rectal, oral
**Transmission:** vertical, horizontal (sex)
**Disease:** gonorrhea or related PID
* Sticky purlent discharge
52
VF of N. gonorrhoeae
Pili for adherence
53
What are you G- cocci?
Neisseeria:
1. menigitides
2. gonorrhoeae
53
Moraxella catarrhalis
| Classification, Location, Disease
**Classification:**
* Oxidase +
* Catalase +
* Obligate aerobe
* Non-motil
* LPS endotoxin
* B-lactamases
**Location:** Upper respiratory tract
**DIsease:** sinusitis, otitis media infection
54
Haemophilus influenzae
| Classification, Location, Disease
**Classification:**
* Facultative anaerobes, catalase +, oxidase +
* Pleomorphic, thick capsule
* 6 caqpsular serotypes exist
* Fastidious
**Location:** upper respiratory tract (throat)
**Transmission:** respiratory droplets
**Dx:** pneumonia, meningitis
55
What bacteria is the leading cause of bacterial meningitis?
Haemophilus influenzae
56
VF of Haemophilus influenzae?
1. IgA protease
2. Hib capsule
3. endotoxin
4. pili
57
What are you G- coccobacilli?
1. Moraxella
2. Haemophilus influenzae
58
Aeromonas
| Classification, Location, Disease
**Classification:**
* Lactose fermenter
* Catalase +
* Oxidase +
**Location:** brackish water, contaminated food
**Disease:** dysentery, cellulitis, opportunistic infection
59
VF of thee Aeromonas?
1. Adhesion (flagella, pilli)
2. Hemolysins
3. Siderophores
4. Endotoxin
5. Enterotoxins
6. MDR
60
Vibrio
| Classification, Location, Transmission, Disease
**Classification:**
* Lactose ferementer
* Oxidase +
* O-antigen
**Location:** GI mucous membrane
**Transmission:** Fecal-oral food and water
**Disease:** Vibrio cholerae
61
Bacteria that cause rice water stool?
Vibrio
62
Describe the characterisitcs of the cholera toxin?
Rice water stool -> dehydration:
1. B part of toxin binds to GI epithelial cells
2. A part enters cells to increase cAMP levels -> active secretion of ions from cell
63
Escherichia coli
| Classification, Location, Disease
**CLassification:**
* faculatative anaeerobe
* Catalase +
* Oxidase -
* Fermenter of glucose and lactose
* O antigen
**Location:** GIT
**Disease:** opportunistic, water diarrhea, dysentery
64
VF of E coli?
1. Capsule and fimbriae to adhere to mucosal surfaces
2. Hemolysins
3. Siderophores
4. Enterotoxins
5. Motile due to flagella
65
How can MacConkey detect lactose fermenters?
Pink colonies
66
What E.coli strain is a major cause of UTI in healthy individuals?
UPEC
67
What E. coli stain produces enterotoxins that cause diarrhea without destroying the cells of the intestines?
ETEC
* traveler's diarrhea
* heat stable enterotoxin and heat labile enterotoxin
* Fecal oral from contaminated food
68
What E. coli strain destroys intestinal lining, kidney failure, and hemolytic uremic syndrome?
Enterohemorrhagic (EHEC) 0157:H7 E. coli
* produces shiga toxin -> inhibits protein synthesis
* Abdominal cramps, diarrhea, fever, vomiting
* Causes severe foodborne disease from raw food
69
Klebsiella
| Classification, Location, Transmission, Disease
**Classification:**
* faculative anearobe
* Oxidase -
* Lactose fermenting
* Urease +
**Location:** GI and GUT
**Transmission:** Horizontal
**Disease:** Pneumonia, UTI, wound infection, sepsis, alveolar necrosis, nosocomial infection
70
VF of Klebsiella
1. Fimbriae
2. Siderophores
71
Eneterobacter
| Classification, Location, Transmission, DIsease
**Classification:**
* facultative anaerobe
* Oxidase -
* Motile
* Feremtner
* Urease +
**Location:** GIT
**Transmission:** Horizontal
**Disease:** nosocomial
72
VF of Enterobacter?
1. Fimbriae
2. LPS
3. Capsule
4. Hemolysins
5. Siderophores
73
Citrobacter
| Classification, Location, Disease
**Classification:**
* Facultative anaerobe
* Oxidase -
* Lactose-fermenting, use citrate as carbon source
* Motile (flagella)
**Location:** GIT and soil
**Transmission:** Vehicle from contaminated food
**Disease:** diarrhea, UTI, pneumonia, nosocomial infection (shiga toxin)
74
VF of Citrobacter?
1. Flagella
2. LPS
3. Shiga toxin
75
Campylobacter jejuni
| Classification, Location, Transmission, Disease
**Classification:**
* Microaerophile
* Oxidase +
* Urease -
* Non-fermenter
**Location:** GIT
**Transmission:** animals to humans by fecal oral route, COntaminated meat, milk, water
**Dx:** foodbourne illness, dysentery
76
VF of Campylobacter jejuni?
1. Adhesion
2. Cytolysins
3. Hemolysins
77
Helicobacter pylori
| Classifcation, Location, DIsease
**Classification:**
* Enteric GNR
* Motile
* oxudase +
* Non fermenter
* Catalase -
* Urease
**Location:** Lower stomach, intestines
**Disease:** acute and chronic gastritis, peptic ulcers, and gastric cancer
78
Pseudomonas aeruginosa
| Classification, Location, Disease
**Classification:**
* Polar flagella
* Obligate aerobe
* Catalase +
* Oxidase +
* b-hemolytic
* Non fermenter
**Location:** soil and moist reservious
**Dx:** Opportunistic
79
What type of bacteria is green in color and grown on blood agar?
Pseudomonas aeruginosa
80
VF of Pseudomonas aeruginosa?
1. Flagella
2. Pilli
3. Exotoxins
4. Proteases
5. b-lactamases
81
What are your non-enteric G- bacilli?
1. Pseudomonas aeruginosa
2. Acinetobacter
3. Bordetella
4. Legionella
82
What are you enteric GNR G- bacilli?
1. Serratia
2. Proteus
3. H. pylori
4. Klebsiella
5. Enterobacter
6. Citrobacter
83
What are your GI G- bacilli?
1. Campylobacter jejuni
2. Salmonella
3. Shigella
84
Serratia
| Classification, Location, Disease
**Classification:**
* enteric
* Oxidase -
* Non feremetner
* Motile
**Location:** UT, lower respi
**Disease:** Opportunistic and nosocomial pathogens, UTI, lower resp infection
85
Proteus
| Classification, Disease
**Classification:**
* enteric
* Oxidase -
* Non feremetner
* Motile
* urease +
* Causes formation of insoluble phosphates and magnesium stones (struvite stones
**Disease:** Nosocomial UTI
86
Salmonella enterica
| Classification, Location, Transmission, Disease
**Classification:**
* Faculative anaerobes
* Non fermenter
* Catalase +
* Oxidase -
**Location:** Attach to mucosa in small intestine and enter enterocytes and Peyer patches and be transported into the blood or lymph
**Transmission:** eating contaminated food or by fecal-oral spread
**Dx:** Dysentery, enteric fever (typhoid)
87
VF of Salmonella
Can survive in macrophages, neutrophils and DCs and spread from the intestine to other body sites or blood
* Release typhoid toxin -> cell senescence allowing bacteria to hide and replicate
88
Shigella sonnei
| Classification, Location, Transmission, Dx
**Classification:**
* Non motile
* Facultative anaerobes
* No fermentation or oxidase
**Location:** GIT
**Transmission:** fecal contaminated food
**Dx:** FBI, dysentery
89
VF of shigella sonnei
1. Invades and destroys the mucosa of large intestine -> dysentery
2. Exotoxin with enterotoxic and cytotoxic properties fro shiga toxin -> inhibits protein synthesis
3. Reproduce intracellularly with invasins
4. O antigen of LPS
90
Bordetella pertussis
| Classification, Disease
**Classification:**
* Encapsulated
* Aerobic, oxidase +
* Fimbraiae
**Disease:** upper respiratory infection, pertussis
* Vaccine- TDaP
91
Acinetobacter
| Classification, Disease
**Classification:**
* Obligate aerobe
* Oxidase -
* Opportunisitc
**Disease:** Nosocomial wound and pulmonary infections
92
Legionella
| Classification, Transmission, Disease
**Classification:**
* Aerobic
* Uncap
**Transmission:** aerosolized water
**Dx:** Respiratory infection
93
VF of Legionella
1. Chlorine tolerant
2. Intracellular pathogen: blocks lysosome while replicating in macrophages
94
What are the nosocomial pathogens that exhibit MDR?
1. Enterococcus faecium
2. Staphylococcus aureus
3. Klebsiella pneumoniae
4. Acinetobacter baumannii
5. Pseudomonas aeruginosa
6. Enterobacter spp
* E. coli
95
What are spirochetes?
1. Slender and tightly coiled bacteria
2. Visible by darkfield microscopy not by Gram stain
3. Move by using periplasmic flagella
4. Protoplasmic cylinder
96
What are the types of atypical spirochetes?
1. Treponema
2. Borrelia
3. Leptospira
97
Treponema pallidum
| Classification, Transmission, Disease
**Classification:** Atypical spirochetes
**Transmission:** Direct contact on lesions of skin and mucous membranes
* Vertical
**Dx:** syphilis
98
How does Terponema enter the body?
1. enters through breaks in mucosal membranes and skin
2. Prefers to grow in lower temperatures so lesions are found on lips, tongue, and genitalia
3. Spreads through blood and lymph
4. Fastidious and fragile
99
What enzyme is produced by Treponema?
Hyaluronidase
100
Borrelia burgdorferi
| Classification, Location, Transmission, Disease
**Classification:**
* No toxins
**Location:** Spread from the site of the tick bite to the surrounding skin
**Transmission:**
* Reservoir is small mammals
* Transmitted by arthropod bites
**Disease:** Lyme and relapsing fever
101
What are the stages of Lyme?
**1:** spread from the site of the tick bite to the surrounding skin
**2:** 2-cardiac and neurologic involvement (weeks-months)
**3:** Arthritis
102
Describe the life cycle of borrelia?
103
How do atypical bacteria differ from other groups?
1. No typical G stain
2. Facultative intracellular bacteria can replicate inside or outside of host
3. Facultative intracellular bacteria can replicate inside or outside of host
104
What bacteria invade host cells as a means of protection from the immune system?
Mycobacterium, Mycoplasm
105
What bacteria utilizes host's cellular machinery to replicate?
Chlamydia, Rickettsia
106
How does mycoplasma differ from other atypicals?
Lack a cell wall
* Bound by a cell membrane lacking peptidoglycans
* Contains lots of sterols in membrane
107
Disease acquired from Mycoplasma?
Community-acquired walking or atypical pneumonia
108
How does Mycobacterium differ from other bacteria?
1. Strictly aerobic and have slow generation times
2. Contains Mycolic acid therefore can use an acid fast stain to ID
109
Mycobacterium tuberculosis
| Classification, Trasmission
**Classification:** Atypical that causes TB, obligate aerobe
**Transmission:** Respiratory droplets
110
Describe the mechanism of m. tuberculosis?
1. Inhibits phagolysosome
2. Causes a delayed type hypersensitivity resulting in formation of destructive multinucleate giant cells and granulomas -> destroying lung tissue
3. Granulomas develop when there is continuous activation of macrophages
4. Granulomas release large amounts of lytic enzymes that damage blood vessels and lead to tissue necrosis--granulomatous response.
5. Can cause latent infection
111
Describe the characteristics of Chlamydiae?
1. Obligate intracellular atypical
* Rely on host to make ATP (energy parasites)
* Block fusion of the phagosome with the lysosome
* Have a rigid cell envelope with 2 lipid bilayers with LPS, but with no peptidoglycan
112
Disease caused by Chlamydiae?
Chlamydia that can cause urethritis (discharge and pain with urination), cervicitis, and conjunctivitis (can lead to corneal scarring)
* Asymptomatic in females
* Symptomatic in males
113
What bacteria utilizes elementary body?
Chlamydiae
114
Describe the life cycle of chlamydiae?
1. EB attaches to receptor on host cell
2. EB enters host cell by endocytosis
3. EB converts into RB in vesicle
4. RB undergoes binary fission producing inclusion bodies
5. RB udergoes more binary fission to form EBs
6. EBs are released from host and infects others
115
How is Rickettsia trasmitted?
arthropod vector (deer and dog ticks)
116
Dx caused by Rickettsia?
Rocky mountain spotted fever:
* Vascularitis, endothelial damage, edema
* arthropod vector (deer and dog ticks)
